Automatic cut-off tool having variable speed drive for coiling machines



C. BOSCHIERO Feb. 4, 1964 3,120,258 AUTOMATIC CUI'OFF TOOL HAVINGVARIABLE SPEED DRIVE FOR COILING MACHINES 2 Sheets-Sheet 1 Filed March8. 1961 FIG2 INVENTQR. Cor-Fade Bosch l are A++orneys Feb. 4, 1964BOSCHIERO 3,120,258

C. AUTOMATIC CUT-OFF T HAVING VARIABLE SPEED DRIVE FOR LING MACHINESFiled March 8, 1961 I 2 Sheets-Sheet 2 INVENTQR. Covrado BoschleroUnited States Patent A' "S gh EA it? UK QIFF TGGL HAVEJG VARIABLE SPEEDERNIE Fflii MA CHENB Corrado Bosehiero, Milm, ltaly, assignor toEirnplex- Rapid, Milo ltaly, a corporation of Italy Filed Mar. S, 1951,Ser. 94,339 Claim" priority, application ltaly Dec. 1'7, 196% 2 Claims.(ill. l53-6) Coiling machines for the manufacture of every type andshape of springs (tensile, compression, cylindrical, conical, biconical,right-hand, left-hand, and similar types) are commonly known on themarket, and in which the wire from which the spring is to bemanufactured is fed through hardened steel guides by one or more couplesof feed rollers suitably seated on two suitably distanced and adjustablegooved blocks which determine the required, bending radius of thespring. The development of the spring depends on the time, on the basisof which, the feeding of the wire is effected prior to the interruptionof the feeding, and after which, with the wire stationary, the cuttingtool or knife is lowered in order to cut the wire. The wire is then madeto advance for a distance equal to the development length of the nextspring.

it is commonly known to those skilled in the art to which the presentinvention pertains, that any type of spring is subjected to stressfatigue, and that such material stress, after a given period of time orcycles provokes breakage of the spring.

Many factors contribute towards the breaking of springs, depending fromthe homogeneous characteristics of the material, of the heat treatmentto which it has been submitted, and the processing system employed inthe manufacture of the sprin Ornitting or leaving out of considerationthe first two causes, it has been found that a spring usually breaksalmost always in the first coils, and which goes to indicate that thematerial is subjected to major stress during the early part of thewinding operation, and that is to say as soon as the material hascommenced to be fed forward. This is due to the instantaneousacceleration, and surge force to which the wire is subjected, andespecially when the wire has a small diameter. This yielding is lateraggravated by the continuous bending stress made upon the flexiblequalities of the wire caused by the helicoidal folding of the wire. Thisis particularly the case with springs having a small bending radius.This defect in the manufacture of springs is also the cause ofinconsistent load bearing capacities in springs of the s oe size.

All these defects become abolished according to the present invention,by eliminating the interruption in the feeding of the wire heretoforenecessary with this type of machine to effect the cutting operation ofthe wire at a pro-established length thereof that is to say by arrangingthat the cutting-off operation of the wire takes place simultaneouslywith the feeding operation. in this way, all of the periods ofnon-operation, due to the discontinuance of the wire feed, areeliminated, and accordingly the output production is increased. For thispurpose a mechanism suitable for accomplishing this operation isprovided.

Therefore, all lost time derived from the continuous interruptions in feding operations are eliminated, and at the same time increasing theproduction output of the springs, this being achieved with the use of aknife or mobile cutting-elf tool, and having a speed equal to or.

could be in an alternating straight line, circular, oscillating, orsimilar motion, inasmuch as one of the characteristics of the inventionis that said knife when in the cutting position is furnished with amovement, comprised of a first movement equal or similar to the wirealready spring wound, and having a speed as defined above, and a secondpenetrating movement almost perpendicular to the fi st with which toeffect the cutting-off of the wire.

Another feature of the invention is contained in the provision of adevice to command the cutting-off knife at the exact moment when thewire has to be cutoff, inasmuch as inexactness in this operation wouldcause a greater or smaller overall development length of the spring,because the feeding of the wire continues during the cutting-offoperation.

A further aim of the invention is to provide a driving device suited tosupply the cam carrying shaft with a practically infinite range ofrotary speeds.

Another aim of the invention is to providea means suited to adjustingthe rotary speed of the cam shaft, having the adjustment effected fromthe exterior, and without interruption to the movements of the machineand with direct reading on a suitably calibrated dial. This is obtainedby substituting the gear train used up to the presout day, and which hasto be suitably arranged for each length and pitch of spring, by means ofany type of variator which controls the cam shaft through a practicallyinfinite range of speeds. This latter, in turn, through a system oflevers, operates in an intermittent manner, the cutting knife whichreceives its motion from a coupling means coupled to the main drive. Inthis manner the cutting knife can be instantaneously controlled at aspeed equal or greater to that of the feed wire speed.

The adjustment of the speed of the cam shaft obtained through theaforesaid speed variator, which in turn receives its motion through theone unique drive motor wmch feeds the wire independently of saidvibrator, can be obtained by means of a hand wheel acting on thevariator, and which is connected to the index of a suitably calibratedgraduated dial.

A form of the embodiment of the present invention, given forillustration purposes, and not limited to the scope of the invention isgiven as follows and with reference to the attached drawings in which:

FIG. 1 is a side View of the Winding machine for the production ofsprings in accordance with the present invention.

FIG. 2 is a front vieW of the same partially opened to give an interiorview.

FIG. 3 is a section along line AA of FIG. 4 of a mechanical clutch forthe transmission of the rotary movement derived from a motor, through aseries of gears, based on the control drive given to the clutchmechanism by a cam to said clutch, which operates the cutthig-oif knifethrough a system of levers.

FIGS. 4 and 5 are both a front view of said mechanical engager or clutchin the respective positions of engagement and disengagement.

FIGS. 6 and 7 respectively, show a front view of said cam drive systemin the disengaged and engaged positions.

The winding machine for the manufacture of springs in accordance withthe present invention comprises a body principally composed of a plateand frontal upright mounting l, and a rear plate and mounting upright1', together with a base 2. On the base 2, is installed a motor 3 theoutlet shaft of which drives a pulley 5, by means of a pulley 4, keyedonto the outlet shaft of the motor, said pulleys being connected up bydrive belt 6.

On a shaft 7, on which is fitted pulley 5, there is also a key fittedgear 8, which meshes with gear 9, which in turn transmits the rotarymotion, through the intermediary gear 10, to rollers i1 and 12 whichdraw in the wire 13, in collaboration with two oppositely situatedrollers 14, and 15, which are held tightly against the two underlyingrollers 11 and 12 by the adjustable springs 16. Said rollers 11, 12, 14,and 15 in hardened steel are furnished with peripheral grooves for thedrawing of the wire.

From the roller 12, the motion is transmitted through gears 17, 18, 35,2t? and 21 which have a given ratio to the two perfectly equal gears 22,which eccentrically carry a turret 58 which supports the knife 23, beingadjustable in height, and such knife remains always in a given positionbeing preferably vertical, inasmuch as the two gears are perfectlysimilar to each other. In this manner the cutting knife can execute acircular motion in correspondence with the eccentricity value, and witha speed ratio in correspondence with that of the speed of the wire feed.Thisvelocity is preferably equal or greater than that of the speed ofthe wire feed rate. The cutting-off knife cuts off the helicoidal woundwire by means of the adjustable channelled blocks 56 in collaborationwith a counterknife 57. a

The rotation of the cam shaft 24 is changed by means of a speed variator25 having an infinite range of speeds. Said speed variator is driven ina rotary motion by means of a gear engagement 26, which is keyed ontothe gear shaft 9 From gear part 26, the movement is transmitted by achain 27, to a gear drive 28, which in turn transmits the movement to atoothed wheel 29 by means of a belt drive 3%), of the pulley system6465, or other member of the variator. From gear 29, the movement istransmitted to an'other gear 31, on which shaft is fitted gear 32, whichis'connected by means of chain 33, to gear 34, keyed onto the cam shaft24.

The movement of rotation of gear 29 allows for the periodic rotation'ofthe intermediary gear 21), by means of an instantaneous coupling'of anysuitable type and operated by one of the cams on the cam shaft.

For example an instantaneous type of coupling can be constituted by anelectro-magnetic coupling (not shown) 'in the drawing as these devicesare commonly known to those skilled in the art to which the presentinvention pertains). Whilst this type of coupling is very suitable dueto the fact that it is instantaneous, it is subject to wear, and in sucha manner that after a given period of time becomes unusable and has tobe substituted.

Therefore a mechanical type of coupling means has been proposed andillustrated, and which whilst having a rather less instantaneous action,is perfectly suitable to the purpose, and of almost unlimited wearingqualities, as well as of reliable operating capacity. It is easy tounderstand the importance of providing for this coupling means whenconsidering the fact that the drive action of the knife depends on it,and that the feeding of the wire being interrupted, a delay oranticipation in operating the movement of the knife, which remainsstationary during the winding phase, could cause a variation in thelength of the spring. The mechanical coupling which forms part of thepresent invention is'a multiple tooth device having multiple pawls whichhave the function of engaging the coupling means controlling thecutting-off tool in any tooth position of the coupling means,instantaneously at the completion of every revolution of the cam shaft,operated, by the velocity changer.

This coupling means comprises a gear 35, which is in mesh with gear '18,which continually transmits the motion deriving from the alreadymentioned gears coupled to motor 3; said'gear 35 is free with respect toshaft 37, and is provided with internal saw teeth 35', a gear 36 keyedonto shaft 37 in mesh with gear 2i), an external 1 disc plate 38 keyedonto shaft 37, and engageable by means of a .pin 41 with an internaldisc plat 3? freely mounted'on shaft 37 and having a plurality of slits4d, of a number difierent to that of the saw teeth, and of the samenumber of'pawls 42 having part semi cylindrical portion 42", ahorizontal arm 43 at the upper end of the cylindrical portion 42' of thepawl 42. ending with a cylindrical upward pin 43 which engages in therespective slit 40 of the internal disc plate 33. Between each pin 43'and the right end (see H6. 4) of each slit 49 there is provided a spring44, which tends to push the respective pin 43' towards the other ends ofslit 4%.

The operation of this mechanical coupling means is as follows: As thecam follower 45 pivoted on a pin 46 encounters with its end in contactwith cam 48a step 47 of cam 48 mounted on the cam shaft 24, it carriesout a clockwise movement (FIG. 6) causing cranked lever 49 to beoscillated in a counterclockwise direction against the action of therespective compression spring 59, then arm 51 pivoted on a pivot 52,under the action of tension spring 53 which is in a stressed conditionin FIG. 6, rotates in a counterclockwise direction bringing intorotation the internal disc plate 39 by means of pin '41. With theconsequent counterclockwise rotation of slit 4%? in inner disc 3?, thepins 43 which are in the disengaged position against the respective endof slits 4i opposed to those on which springs 44 rest, tend to maintainthemselves in said position under the influence of the respectivesprings 44. This provokes therefore a' rotation of pawls 42 until one ofwhich through its semicylindrical portion or section engages the cavityof one of the saw teeth 35' in continuous rotation. in this manner pin43' of the pawl 42 in engagement with a saw tooth operates, by pressingagainst the end of the respective slot 40, the inner disc 39. This disc39, through pin 4l'and arm 51 which is coupled through pivot 52, toplate 38, rotates said plate. This plate, being keyed to shaft 34,rotates gear 36 which is keyed to the shaft 34. Gear 36 in turntransmits the rotation to gear 2i) and thus the operating motion to thecutting-off knife 23. 7

After one turn of the external disc 38, the arm carried by this lattercomes again into contact with the stop constituted by the crank lever49. The external disc 38 continues to rotate extending the spring '53,whilst pin 41 remains stationary, and therefore also stops the movementof internal disc plate 39. The pawls 42 through its lower portion 42"continue to be drawn along by the saw teeth, whilst pins 43 remainstationary; therefore the semicylindrical portion 42" revolves arounditself causing it to "be freed from its seat in the cavities of the sawteeth, and shaft 37 is brought to a standstill.

In order to block gear 36always in a given position,

a roller 59 is provided carried by an arm 62 pivoted on a pin 63; saidarm is subjected to the action of a spring 61. Said roller 59 under theaction of spring 61 'fits into a recess 66 provided in .said gear 36 insuch a manner as to block it. Arm 62 with the respective roller isnecessary in that, if there were no stopping means provided for shaft 37when the whole assembly returns into the disengaged position, spring 53would tend to rotate all the assembly in a clockwise direction, andparticularly disc plate 38: in such a manner also pivot pin 52 is movedand accordingly lever. 51 changes position. In the meanwhile, also shaft37 which draws along 'pawls 42, continues to rotate under the action ofspring pawls 42, the more instantaneous will be the engagement.

The time interval for the engagement and disengagement is equal to theinterval between one tooth and .another 'divided by the number of saidengaging pawls.

The adjustment control of the overall development of the spring to bemanufactured is therefore the time interval between one engagement andanother of the Pawls 42 U cutting-oil tool, and depends on the speedassumed by the cam shaft controlled by the speed variator.

Said speed can be continuously changed without interrupting theadvancement of the Wire or the rotation of the cam shaft. The rotaryspeed of the cam shaft, and therefore the development of the spring orlength of the wire which is needed for a spring can be directly read andregulated by manipulating the variator control wheel 54, observing suchvalues on a dial 55. The pointer of the dial 55 is directly connected tothe hand wheel 54 by means of the transmission 66, 67, 68. Then thepulley 68 acts on a pulley 69 of a conventional variator provided by thetwo pulleys 64 and 65.

In this manner, the machine has to be regulated simply on the basis ofthe development of the spring, and which can be read on the dial 55, andit is no longer necessary to calculate the gear train to be mounted.

The attached drawings do not show the various devices and transmissionsfor the production of helical springs, right-hand, left-hand, andsimilar types, as these are commonly known and do not enter into thescope of the invention.

Vlhilst a specific form of embodiment of the present invention has beendescribed and illustrated, it is understood that various modificationsand changes can be evolved without exceeding the scope limits of thepresent invention as it is understandable that the type of movement ofthe cutting off tool, the engaging device for the tool, and thearrangement of the various operating units, as well as the type ofvariator employed have no importance in this specific regard.

What I claim is:

1. In a winding machine for the manufacture of springs, a cutting-oiltool having a normal cutting movement at regular intervals, a speedvariator for controlling the movements of the cutting-off tool, a motorconnected to the speed variator, a coupling for controlling thecutting-off tool movement, said coupling being engageable ordisengageable and which coupling includes: a shaft having a gear mountedon it and which, through other gears, transmits its movement to thecutting-oil tool, an external disc plate, an internal disc plate freelyrotative around the shaft and having a plurality of slits arrangedaround a common circumference, the two disc plates being connected toone another by means of a pin, a second gear in constant mesh with thefirstmentioned gear, the internal periphery of said second gear havingmultiple saw teeth in a number different from the slits in the internaldisc plate, a number of pawls equal in number to the number of slits,said pawls having semi-cylindrical extremities in contact with thesecond gear and also having an arm provided with a pin engaged in theslits, a spring located in each slit between an extremity of the sameand a respective pin, an arm (51) arranged on the external face of theexternal disc plate and pivoted on a pivot pin, a tensile springanchored externally to the free end of the arm, and a roller carried bya pivoted spring-biased arm (62) and urged into a recess on theperiphery of the second gear.

2. In a windin machine for the manufacture of springs and which machineincludes means for feeding springforming wire, the improvementscomprising a cutting-off tool having a cutting movement at regularintervals, means for applying movement to the cutting-oil tool to movesaid cutting-oh" tool in the direction of winding of the spring-formingwire and with a speed at least equal to the rate of speed of the wirewhereby the feeding of the wire is not interrupted during the cuttingoperation, a coupling for controlling the cutting-oif tool movement,means for controlling the engagement or disengagement of said couplingincluding a cam, a cam follower located between the cam and coupling,said cam follower having one end resting on the cam and its other endresting on the end of a crank lever (49), the other end of the cranklever coming into contact with an arm (51) to act as a stop for saidarm.

References Cited in the file of this patent UNITED STATES PATENTS1,040,196 Harter Oct. 1, 1912 1,556,405 Blevel Oct. 6, 1925 FOREIGNPATENTS 528,499 Great Britain Oct. 30, 1940

1. IN A WINDING MACHINE FOR THE MANUFACTURE OF SPRINGS, A CUTTING-OFFTOOL HAVING A NORMAL CUTTING MOVEMENT AT REGULAR INTERVALS, A SPEEDVARIATOR FOR CONTROLLING THE MOVEMENTS OF THE CUTTING-OFF TOOL, A MOTORCONNECTED TO THE SPEED VARIATOR, A COUPLING FOR CONTROLLING THECUTTING-OFF TOOL MOVEMENT, SAID COUPLING BEING ENGAGEABLE ORDISENGAGEABLE AND WHICH COUPLING INCLUDES; A SHAFT HAVING A GEAR MOUNTEDON IT AND WHICH, THROUGH OTHER GEARS, TRANSMITS ITS MOVEMENT TO THECUTTING-OFF TOOL, AN EXTERNAL DISC PLATE, AN INTERNAL DISC PLATE FREELYROTATIVE AROUND THE SHAFT AND HAVING A PLURALITY OF SLITS ARRANGEDAROUND A COMMON CIRCUMFERENCE, THE TWO DISC PLATES BEING CONNECTED TOONE ANOTHER BY MEANS OF A PIN, A SECOND GEAR IN CONSTANT MESH WITH THEFIRSTMENTIONED GEAR, THE INTERNAL PERIPHERY OF SAID SECOND GEAR HAVINGMULTIPLE SAW TEETH IN A NUMBER DIFFERENT FROM THE SLITS IN THE INTERNALDISC PLATE, A NUMBER OF PAWLS EQUAL IN NUMBER TO THE NUMBER OF SLITS,SAID PAWLS HAVING SEMI-CYLINDRICAL EXTREMITIES IN CONTACT WITH THESECOND GEAR AND ALSO HAVING AN ARM PROVIDED WITH A PIN ENGAGED IN THESLITS, A SPRING LOCATED IN EACH SLIT BETWEEN AN EXTREMITY OF THE SAMEAND A RESPECTIVE PIN, AN ARM (51) ARRANGED ON THE EXTERNAL FACE OF THEEXTERNAL DISC PLATE AND PIVOTED ON A PIVOT PIN, A TENSILE SPRINGANCHORED EXTERNALLY TO THE FREE END OF THE ARM, AND A ROLLER CARRIED BYA PIVOTED SPRING-BIASED ARM (62) AND URGED INTO A RECESS ON THEPERIPHERY OF THE SECOND GEAR.